1. Technical Field
This invention generally relates to an apparatus for heating the air/fuel mixture entering the cylinder of an internal combustion engine. More particularly, the invention relates to an electric heating element recessed into a cylinder head and electrically connected to a power source by a terminal assembly. The terminal assembly is coupled to the heating element and passes through an aperture formed in the cylinder head.
2. Discussion
The prior art has addressed the desirability of heating the environment of the intake manifold including the air/fuel mixture exiting the carburetor of an internal combustion engine in order to increase fuel economy and decrease pollutant discharge. One type of intake heating device generally includes a pair of gaskets surrounding a heating coil or grid disposed between the carburetor and the air intake manifold as shown in U.S. Pat. No. 4,020,812 to Hayward and U.S. Pat. No. 4,106,454 to Henlis. Unfortunately, gasket wear or aging may eventually lead to contact between the contacts of the heater element and either the intake manifold or the carburetor thereby shorting the electric circuit through the heater element. As gasket aging is partially attributable to the heat generated by the contacts adjacent to the gaskets, the power and voltage used in the heating system may be limited by concerns over the useful life of the gaskets.
Stand alone heating devices such as the diesel fuel heating plate shown in U.S. Pat. No. 4,501,255 to VanDerPoleg et al. have also been developed. While these designs may eliminate the problem of shorting due to gasket wear by relocating the electric contacts of the heating device, the height of the stand alone units effectively increase the distance between engine elements located above and below the heater. Accordingly, wires, hoses, tubes and the like such as those used in fuel lines, intake air plumbing and turbocharger and aftercooler assemblies often must be lengthened to accommodate the increased distance. Thus, it was required to maintain an expanded inventory of such wires, hoses, tubes and the like to accommodate engines with and those without the stand alone heating devices.
One object of the present invention is to provide an improved electric heater device which eliminates the potential for short circuiting due to gasket wear.
Another object of the present invention is to allow increased power transmission through the heater element thereby increasing the capacity of the element to heat the air passing therethrough.
It is an additional object of this invention to reduce the effective height of the heater device thereby eliminating the need to maintain an expanded inventory of connecting wires, hoses, tubes and the like.